Memantine (Mem), an uncompetitive antagonist of the N-methyl-D-aspartate receptor (NMDAr), has demonstrated neuroprotective effects in preclinical stroke models by reducing excitotoxic damage. However Show more
Memantine (Mem), an uncompetitive antagonist of the N-methyl-D-aspartate receptor (NMDAr), has demonstrated neuroprotective effects in preclinical stroke models by reducing excitotoxic damage. However, the efficacy of low acute doses administered during the immediate post-ischemic phase remains insufficiently characterized. Male rats underwent permanent middle cerebral artery occlusion (pMCAO) and received a single intraperitoneal dose of Mem (5 mg/kg) two hours post-occlusion. Neurological deficits were assessed using the modified Neurological Severity Score (mNSS). Infarct area and neuronal preservation were quantified using MAP2 immunohistochemistry. BDNF and PSD95 protein levels were measured by ELISA, and their gene expression was evaluated via RT-PCR. Mem treatment significantly reduced infarct area (p = 0.000029) and attenuated neurological deficits (p < 0.0001). MAP2 immunoreactivity was higher in the Mem-treated group (p = 0.000003), indicating preservation of neuronal structure. BDNF protein levels did not differ between the pMCAO and pMCAO+Mem groups; PSD95 protein and its corresponding DLG4 mRNA were increased in the pMCAO group compared with Sham. In the other groups, levels remained unchanged. Early administration of low-dose memantine confers acute neuroprotection after stroke by reducing tissue damage and preserving neuronal integrity, without affecting ischemia-induced BDNF and PSD95 protein and gene expression. These findings suggest a selective early neuroprotective mechanism and highlight the need for long-term and sex-inclusive studies to further evaluate memantine's therapeutic potential. Show less